A process for manipulating magnetic particles suspended in a fluid that are able to bind to an entity of interest, the fluid being contained in a reaction vessel having a large funnel shaped upper compartment, an elongate lower compartment of substantially constant cross-section and a closed base. The process consists of: a) subjecting the magnetic particles to two simultaneously applied magnetic fields to separate all said magnetic particles present in at least the upper compartment of the vessel from the fluid, b) transferring the separated magnetic particles from the upper compartment to the lower compartment, c) removing the fluid from the vessel, d) adding a washing liquid to the lower compartment, e) subjecting the magnetic particles to at least two magnetic fields applied successively with changing directions to wash all the magnetic particles present in the lower compartment, and concentrating said magnetic particles in said lower compartment.